Boom attachment for lift truck



Sept 2l, 1965 s. v. EHRLlcH 3,207,347

BOOM ATTACHMENT FOR LIFT TRUCK Filed Aug. 26, 1963 2 Sheets-Sheet lSTANLEY l/. EHRL/CH /NVE/VTR 36 By BUCH/OHM ELO/QE, KLA/POU/ST SPAR/(MANAHORA/srs Sept. 21, 1965 s. v. EHRLlcH 3,207,347

BOOM ATTACHMENT FOR LIFT TRUCK Filed Aug. 26, 1965 2 Sheets-Sheet 2 44 Fig.8

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STANLEY l( EHRL/CH INVENTOI? BY BUC/(HORN, BLOHE, KLAROU/ST 8 SPAR/(MANATTORNEYS Unted States Patent O 3,207,347 BGM ATTACHMENT FOR LIFT TRUCKStanley V. Ehrlich, 6206 SW. 41st Ave., Portland, Greg. Filed Aug. 26,1963, Ser. No. 304,437 6 Claims. (Cl. 214-620) The present inventionrelates to lift truck attachments and more particularly to a boomattachment for a lift truck.

Boom attachments for lift trucks have been found to be very useful forloading and unloading railroad cars and trucks with sideboards. Suchbooms are especially effective in lifting heavy machinery, engines,structural members, logs and other items which conventional fork armscannot readily handle.

However, previously devised boom attachments are relatively diicult andtime-consuming to mount and detach from a lift truck, and some requireremoval of the fork arms for mounting. Even those boom attachmentsmountable on a lift truck with thelfork arms intact must usually beremoved when it is desired to again use the fork arms.

Accordingly, a primary object of the present invention is to provide anew and improved boom attachment for a lift truck which can be mountedand detached by the lift truck operator alone while he remains at hiscontrols, by a simple manipulation of the fork arms of the truck.

Another primary object of the present invention is to provide a new andimproved boom` attachment for a lift truck which can be swung to aninoperative position on the truck for use of the fork arms.

Another object of the invention is to provide a new and improved boomattachment for a lift truck which can be manipulated by use of theconventional hydraulic load handling mechanisms of the truck.

In fulfillment of the above objects, the boom structure of theattachment includes a trunnion base member which, when the attachment ismounted on a lift truck, rests in the angle of the fork arms thereof.The boom structure is rotatable on the fork arms relative to an uprightpost member which is hooked on the lift carriage of the truck to securethe attachment in position. When in use, the boom structure ismaintained at an angle relative to the post member, but when it isdesired to use the fork arms, the boom structure is simply swung to anupright inoperative position and latched to the post member. The boomstructure is manipulated for lifting loads by lifting the carriage andtilting the mast structure in the usual manner.

The foregoing and other objects and advantages of the present inventionwill be more readily ascertained from inspection of the followingspecication taken in connection with the accompanying drawing whereinlike numerals refer to like parts throughout, while the features ofnovelty will be more distinctly pointed out in the appended claims.

With reference to the drawings:

FIG. 1 is a perspective View showing a boom attachment in accordancewith the present invention in position on a lift truck;

FIG. 2 is an enlarged fragmentary section taken approximately along theline 2-2 of FIG. l showing the boom attachment and the front end portionof a lift truck;

FIG. 3 is a perspective view of the means for securing the boomattachment to the front end of a lift truck;

FIGS. 4 to 6 inclusive are diagrammatic views illustrating the use ofthe boom attachment in lifting objects;

FIG. 7 is a diagrammatic view illustrating the procedure for attachingthe boom on a lift truck;

FIG. 8 is a top plan view of a storage stand for storing the boomattachment when not attached to a lift truck.

3,207,347 Patented Sept. 21, 1965 With reference lirst to FIG. 1,indicated in dotted lines is the forward portion of a lift truck 10 of atype with which the boom attachment of the invention may be utilized.Such truck includes a mast structure 12 comprising opposed pairs ofinner and outer telescoping upright members 14 and 15. The maststructure 12 is pivotally mounted at its lower end on the front end ofthe lift truck frame and is tilted forwardly and rearwardly by means ofhydraulic tilting cylinders 16. A vertically disposed hydraulic ram 18is mounted centrally between the uprights 14, 1S, and is fixed at itsupper end to a cross member 20 attached to the inner telescopinguprights 15. The cross member 20 carries sheaves 22 over which extend apair of lift chains 24. One end of each lift chain 24 is attached to avertically movable carriage 26 and the other end of each chain isanchored to the lift truck frame so that extension of the inner uprights15 by the ram 18 lifts the carriage 26. A pair of fork load arms 28 aremounted on and extend forwardly from the carriage 26 for handling loadsin the usual manner.

Shown in solid lines in FIG. l is a boom attachment constructed inaccordance with the invention and comprising a forwardly and upwardlyextending boom structure 30 including a pair of oppositely disposedchannel members 32 fastened together at their outer ends 34. The channelmembers are iixedly attached in spaced apart relationship at their innerends to a transversely extending cylindrical base member or trunnion 36.

When the boom structure is attached to the lift truck as shown, thetrunnion 36 is freely and rotatably supported in the angle of the forkarms 28 at their intersection with the carriage 26. Mounted on theopposite ends of the trunnion are a pair of circular spacer plates 38 oflarger diameter than the body of the trunnion, which serve to mount theboom structure centrally with respect to the fork arms 28 and to preventlateral displacement of the boom structure. The generally triangularboom structure is reinforced by diagonal braces 39 and cross braces 40extending between the channel members 32. A loading hook 42 is pivotallysuspended from a shaft at the outer end of the boom structure, and apair of tongs 44 is hung from such hook by a load cable 46. Of courseslings or other loading devices, as desired, may be attached to the hook42 in lieu of the tongs 44.

An upright post structure 48 of enclosed box construction is rotatablymounted at its lower end on the trunnion 36 centrally between the endsof such trunnion. For this purpose the lower end of the post structure48 includes a strap 50 which encompasses the trunnion 36. The poststructure is attached in an upright position to the carriage 26 byaxially and laterally adjustable hook mounting means. With referencemore particularly to FIGS. 2 and 3, such means include an adjustablesleeve member 52 slidably mounted on the post 48 and securable in anydesired position on such post by a set screw 53. The sleeve member 52has a pair of arms 54 extending laterally in opposite directions fromopposite sides thereof. On each arm 54 a hook member 56 is slidablymounted. Each hook member 56 may be fixed on the arm 54 at any desireddistance from the post 48 by a set screw 57. The hook portion of eachmember 56 opens downwardly for engaging the top edge of a cross framemember 58 of the lift truck carriage 26. Thus, by adjusting the sleeveto any desired height above the trunnion 36 according to the height ofthe carriage 26 and by adjusting the hook members 56 laterally so as notto interfere with the lift chains 24, the boom attachment may be mountedon any lift truck having a cross frame member 58 as most lift trucks dohave.

With the post member 48 in position on the lift truck as described, theboom structure 30, including the trunnion 36, is rotatable relative tothe lift truck and post structure 48 from a predetermined angularposition as shown in full lines in FIG. 2 to an inoperative, uprightposition shown in dotted lines in juxtaposition with the post 48. Thelatter boom position permits the use of the fork arms 28 with the boomremaining attached to the lift truck. A longitudinally extending pin 60is welded or otherwise secured on the trunnion 36 beneath the strap 50to limit the rotational movement of the boom structure from asubstantially vertical position to a load lifting position ofapproximately 45 degrees as shown by becoming wedged beneath the straps50 when the boom is at 45 degrees. Of course, the desired limit ofrotation of such boom is a matter of choice with the user, but ingeneral a swing angle of 45 degrees will be sufcient for most purposes.

Adjustable means are provided for maintaining the boom structure 30 in apredetermined angular operative position relative to the post structure48. The illustrated means include a length of chain 62 secured at oneend to an ear member 64 at the outer end of the boom structure 30 andadjustably attached at the required distance from such end to the top ofthe post structure 48. As shown in the broken-away portion of FIG. 2 andin FIG. 3, the top end wall 66 of the post 48 is provided with a keyholeaperture 68 through which a length of the chain 62 extends into theinterior of the post. The chain may be secured at any desired positionalong its length to the post by inserting a link thereof in the narrowportion of the keyhole aperture.

Means are also provided on the post 48 for selectively latching the boomstructure 30 in an inoperative, upright position in nesting relationshipwith the post 48, such means including a llatch 70 pivotally mounted onthe post, which cooperatively engages a cross brace 40 of the boomstructure as shown in FIG. 2 when the boom is upright. Two hook ends 71of the latch member 70 are provided with camming surfaces so that theboom structure may be swung to its inoperative position and latched insuch position without the operator ever leaving his controls on the lifttruck. A stop member 72 on the post beneath the latch member 70 preventsthe latch member from swinging below a substantially horizontalposition, and a tie strap 73 between the hook ends 71 limits the upwardswing of the latch. To swing and latch the boom, the mast 14 is simplytilted rearwardly to cause the boom structure 30 to swing against thepost structure and latch itself by the force of its own weight.

FIGS. 4 through 6 illustrate the use of the previously described boomattachment for lifting a load. In FIG. 4 the tilting cylinders 16 areextended to tilt the mast 12 forwardly and thus lower the tongs 44 forengagement with a load 74 on the ground surface. As shown in FIG. 5, themast 12 is then tilted rearwardly preparatory to raising the carriage26. With the mast tilted rearwardly, the ram 18 is extended to raise thecarriage and thus the boom 30 upwardly, whereupon the load 74 may bestacked high atop an existing storage pile 76 as shown in FIG. 6.

When detached from the lift truck, the boom attachment may be stored ona storage stand 80, shown in FIGS. 7 and 8. Such stand includes aVertical post 81 supported on tripod legs 82. A vertically adjustablerack member 84 is slidably mounted on the post 81 and has a pair ofparallel and slightly inclined arms 86, which extend outwardly from thepost over one of the tripod legs 82 as shown in FIG. 8.

In storage, the boom attachment hangs by one of its cross braces 40 onthe arms 86 of the stand, with the trunnion 36 out of engagement withthe ground. In removing the boom attachment from the storage stand 80and mounting it on a lift truck, the lift truck is driven toward thestand with its fork arms 28 in their lowermost position A (FIG. 7) sothat the fork arms will clear the trunnion 36 and so that the hookmember 56 on the pQSt Structure 48 will clear the upper cross member 58of the lift truck carriage 26. Then the fork arms are raised to the fullline position B in which the trunnion engages the fork arms 28 and thehook member 56 engages the carriage cross member 58, in which positionthe boom structure is securely attached to the lift truck. To remove theboom structure from the stand, the fork arms 28 are raised still furtherto the dotted line position C in which position the cross brace 40clears the rack arms 86, thereby enabling the lift truck 10 to be backedaway from the storage stand with the boom attachment fully securedthereto. By disengaging the latch 70, the boom is ready for use. When itis desired to remove the boom structure from the lift truck, the aboveprocedure is followed, but in reverse order.

Having illustrated and described a preferred embodiment of theinvention, it should be apparent to those skilled in the art that theinvention permits of modification in arrangement and detail. I claim asmy invention all such modifications as come within the true spirit andscope of the appended claims.

I claim:

l. In a boom attachment for use with a lift truck including:

(a) a forwardly and rearwardly tilting mast structure,

(b) a vertically movable carriage in association with said maststructure,

(c) fork arms projecting forwardly from said carriage,

(d) said attachment comprising:

(e) a boom structure, including a transversely extending trunnion memberat the base of said boom structure adapted to be rotatably supportedtransversely on said fork arms and positioned at the intersectionbetween the inner ends of said fork arms and an upright portion of saidcarriage,

(f) said trunnion member including means for centering said boomstructure with respect to said fork arms,

(g) a post structure centrally mounted on said trunnion member forrotation relative to said boom structure,

(h) downwardly opening hook means on said post structure for securingsaid post structure in an upright position on said carriage and for atleast partially supporting said attachment on said carriage,

(i) said boom structure being rotatable from a first, inoperativeposition in juxtaposition with said post structure to a second, loadlifting position at a predetermined angle with respect to said poststructure,

(j) means connecting said boom and post structure for maintaining saidboom structure in said load lifting position,

(k) and cooperative means on said post structure and said boom structurefor selectively maintaining said boom structure in said inoperativeposition.

2. In a boom `attachment for use with a lift truck including:

(a) a forwardly and rearwardly tilting mast structure,

(b) la vertically movable carriage in association with said maststructure,

(c) fork arms projecting forwardly from said carriage,

(d) said attachment comprising:

(e) a boom structure, including a transversely extending tr-unnionmember at the base of -said boom structure adapted to be rotatablysupported transversely on -said fork arms and positioned at theintersection between the inner ends of said fork arms and an uprightportion of said carriage,

(f) said trunnion member including means for centering said boomstructure with respect to said fork arms,

(g) a post structure centrally mounted on said trunnion member forrotation relative to said boom structure,

(h) adjustable means on said post structure for securing said poststructure in an upright position on said carriage,

(i) said boom structure being rotatable from a rst, inoperative positionin juxtaposition with said post structure to a second, load liftingposition at a predetermined angle with respect to said post structure,

(j) means connecting said boom and post structure for maintaining saidboom structure in said load lifting position,

(k) and cooperative means on said post structure and said boom structurefor selectviely maintaining said boom structure in said inoperativeposition.

3. A boom attachment according to claim 2, wherein said carriageincludes a cross frame member, and said adjustable means for securing4s-aid post structure in an upright position on said carriage includes asleeve member slidable adjustable axially on said post structure, andlaterally adjustable and downwardly opening hook members on said sleevemember for engaging the upper edge or' said cross frame member.

4. A boom attachment for use with a lift truck includ- (a) a forwardlyand rearwardly tilting mast structure,

(b) -a vertically movable carriage, including -a cross frame member, inassociation with said mast structure,

(c) and load carrying fork arms projecting forwardly from said carriage,

(d) said boom attachment comprising:

(e) a trunnion member freely supported transversely on said fork armsand positioned at the intersection of the inner ends of said fork armsand fan upright portion of said carriage,

(f) said trunnion member including enlarged end -portions for centeringsaid trunnion member on said fork arms,

(g) a boom structure lixedly attached to said trunnion member,

(h) :a post structure perpendicular to said trunnion member androtatably mounted at one end centrally on said trunnion member,

(i) axially and laterally adjustable hook means on said post structurefor engaging the upper edge of said cross frame member and mounting saidpost structure in an upright .position on said carriage,

(j) said boom structure being rotatable on said trunnion from a first,upright position in juxtaposition with `said post structure to a second,predetermined angular position relative to said post structure,

(k) adjustable means in association with said boom structure and saidpost structure for maintaining said -boom structure in said angularposition for lifting a load,

(l) land cooperative latch means on said post structure and said boomstructure for selectively maintaining said boom structure in saidupright position.

5. A boom attachment for a lift truck including a forwardly andrearwardly tilting mast structure, a vertically movable carriage on saidmast structure, and fork arms extending forwardly from said carriage,

(a) said boom attachment comprising:

(b) a trunnion member extending transversely between said fork arms andpositioned at the intersection be tween said fork arms and saidcarriage,

(c) a post structure mounted on said trunnion member and when in anoperative position extending substantially vertically upwardlytherefrom,

(d) means Imovable on said post structure for engaging and disengagingsaid carriage by relative sliding movement between said means and saidcarriage such that said attachment can be slidably detached from -andattached to said lift truck,

(e) a boom structure tixedly mounted on said trunnion member and when inan operative position extending angularly upwardly and forwardlytherefrom,

(f) means mounting said boom structure for rotation relative to saidpost structure from said operative position to a substantially Verticalposition adjacent said post structure.

6. A boom attachment for a lift truck including a vertically movablecarriage structure and fork arms extending forwardly `from said carriagestructure,

(a) said boom attachment comprising:

(b) a boom structure supportable at its lower end in the corner definedby said fork arms yand said carriage such that said boom structure canbe moved vertically upwardly relative to said fork arms,

(c) an upright support structure joined at its lower end to lthe lowerend of said boom structure,

(d) means mounting said boom structure and said support structure forrotation relative to one 4another for selective positioning of said boomstructure,

(e) said support structure including downwardly opening hook means forsecuring said support structure and movable on said support structure ina subst-antially vertical disposition to said carriage such thatrelative vertical movement between said hook means and the carriage of alift truck effects detachment of said attachment from said lift truck.

References Cited by the Examiner UNITED STATES PATENTS 2,493,750 1/50Bucksath 214-620 2,617,628 11/52 Wagner 214-127 2,760,661 8/56 Wightetal 214-620 2,820,561 1/58 Meagher 214-620 2,831,592 4/58 Syracuse214-620 2,832,489 4/58 Bailey 214-620 2,840,255 6/58 Pollard 214-6202,990,074 6/61 Berquist et al. 214-620 HUGO O. SCHULZ, Primary Examiner.

MORRIS TEMIN, Examiner.

1. IN A BOOM ATTACHMENT FOR USE WITH A LIFT TRUCK INCLUDING: (A) AFORWARDLY AND REARWARDLY TILTING MAST STRUCTURE, (B) A VERTICALLYMOVABLE CARRIAGE IN ASSOCATION WITH SAID MAST STRUCTURE, (C) FORK ARMSPROJECTING FORWARDLY FROM SAID CARRIAGE, (D) SAID ATTACHMENT COMPRISING:(E) A BOOM STRUCTURE, INCLUDING A TRANSVERSELY EXTENDING TRUNNION MEMBERAT THE BASE OF SAID BOOM STRUCTURE ADAPTED TO BE ROTATABLY SUPPORTEDTRANSVERSELY ON SAID FORK ARMS AND POSITIONED AT THE INTERSECTIONBETWEEN THE INNER ENDS OF SAID FORK ARMS AND AN UPRIGHT PORTION OF SAIDCARRIAGE, (F) SAID TRUNNION MEMBER INCLUDING MEANS FOR CENTERING SAIDBOOM STRUCTURE WITH RESPECT TO SAID FORK ARMS, (G) A POST STRUCTURECENTRALLY MOUNTED ON SAID TRUNNION MEMBERR FOR ROTATION RELATIVE TO SAIDBOOM STRUCTURE, (H) DOWNWARDLY OPENING HOOK MEANS ON SAID POST STRUCTUREFOR SECURING SAID POST STRUCTURE IN AN UPRIGHT POSITION ON SAID CARRIAGEAND FOR AT LEAST PARTIALLY SUPPORTING SAID ATTACHMENT ON SAID CARRIAGE,(I) SAID BOOM STRUCTURE BEING ROTATABLE FROM A FIRST, INOPERATIVEPOSITION IN JUXTAPOSITION WITH SAID POST STRUCTURE TO A SECOND, LOADLIFTING POSITION AT A PREDETERMINED ANGLE WITH RESPECT TO SAID POSTSTRUCTURE, (J) MEANS CONNECTING SAID BOOM AND POST STRUCTURE FORMAINTAINING SAID BOOM STRUCTURE IN SAID LOAD LIFTING POSITION, (K) ANDCOOPERATIVE MEANS ON SAID POST STRUCTURE AND SAID BOOM STRUCTURE FORSELECTIVELY MAINTAINING SAID BOOM STRUCTURE IN SAID INOPERATIVEPOSITION.